Enhancing flux of a microporous hollow fiber membrane

ABSTRACT

The present invention includes a system and method for improving oil recovery from a liquid source of oil, comprising: a membrane contactor in contact with a liquid source of oil; a heating/cooling device connected to at least one of the liquid source of oil or a collection fluid; and a membrane contactor system having one or more membrane contactors having a first and a second surface, wherein at least one of the first or second surfaces coalesce one or more oils from the liquid source of oil allowing the coalesced oil to be collected on the opposite surface of the membrane, wherein a temperature differential between the liquid source of oil and the collection fluid enhances the oil recovery at the membrane contactor from the liquid source of oil.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and is a continuation-in-part ofU.S. patent application Ser. No. 14/100,186, filed Dec. 9, 2013, whichis a continuation-in-part of U.S. patent application Ser. No.14/052,516, filed Oct. 11, 2013, which claims priority to U.S.Provisional Patent Application Ser. No. 61/659,918, filed Jun. 14, 2012and U.S. Ser. No. 61/769,286, filed Feb. 26, 2013. This application isalso a continuation-in-part and claims priority to U.S. patentapplication Ser. No. 13/918,766, filed Jun. 14, 2013; which is acontinuation-in-part and claims priority to U.S. Ser. No. 13/358,897,filed Jan. 26, 2012, now U.S. Pat. No. 8,491,792, which is acontinuation-in-part and claims priority to U.S. Ser. No. 13/280,028,filed Oct. 24, 2011, now U.S. Pat. No. 8,617,396, which is acontinuation-in-part and claims priority to U.S. Ser. No. 13/006,342,filed Jan. 13, 2011, now U.S. Pat. No. 8,486,267, which claims priorityto U.S. Provisional Application Ser. No. 61/295,607, filed Jan. 15,2010, the entire contents of all of which are incorporated herein byreference.

TECHNICAL FIELD OF THE INVENTION

The present invention relates in general to the field of improving oilrecovery, and more particularly, to improving oil recovery and theperformance of a microporous hollow fiber membrane contactor by heatingat least one of a source of oil or a collection fluid.

STATEMENT OF FEDERALLY FUNDED RESEARCH

Not Applicable.

BACKGROUND OF THE INVENTION

Without limiting the scope of the invention, its background is describedin connection with reducing the level of impurities in oils andimproving oil recovery and reclamation.

U.S. Pat. No. 8,128,827, issued to Gallo, et al., teaches a modularoil-based sludge separation and treatment system. Briefly, this patentdiscloses a method of recovering oil from oil-based sludge including thesteps of homogenizing an oil-rich phase, a water-rich phase, and asolids-rich phase of an oil-based sludge, removing particulates from theoil-based sludge as the sludge traverses a shaker screen, heating thesludge, injecting a chemical into the heated sludge and mixing thechemical with the heated sludge, separating the phases of thechemically-treated sludge into a solids component stream, a watercomponent stream, a first oil component stream, and a gas componentstream, removing solids from the first oil component stream with adecanting centrifuge to form a second oil component stream, and removingwater and solids from the second oil component stream with a disk stackcentrifuge.

U.S. Pat. No. 7,186,344, issued to Hughes is directed to amembrane-based fluid treatment system. Briefly, this patent teaches aprocess for removing soluble and insoluble inorganic, organic, andmicrobiological contaminants from a fluid stream employing apretreatment module, a post-treatment module, a recycle stream module orany combination thereof, and a membrane module. The process reduces theproblems associated with membrane fouling and increases contaminantremoval capacity.

United States Patent Application Publication No. 2010/0173806, filed byFan, et al., is directed to the extraction of hydrocarbons fromhydrocarbon-containing materials and includes a method of extractinghydrocarbon-containing organic matter from a hydrocarbon-containingmaterial includes the steps of providing a first liquid comprising aturpentine liquid; contacting the hydrocarbon-containing material withthe turpentine liquid to form an extraction mixture; extracting thehydrocarbon material into the turpentine liquid; and separating theextracted hydrocarbon material from a residual material not extracted.

United States Patent Application Publication No. 2005/0098504 filed byManz, et al., is directed to an oil and gas well fracturing (frac) watertreatment process. Briefly, a novel process for treating and removingundesirable impurities from oil and gas well fracturing fluid isdisclosed. For example, a method for treating fracturing water is taughtcomprising: (a) passing contaminated fracturing water containing solidsand liquid through a mechanical separator to remove solids from theliquid; (b) treating the fracturing water liquid with an alkaline agentto increase the pH of the liquid to a level of above 9; (c) adding acoagulant to the fracturing water to form an agglomerate and separatingthe agglomerate from the fracturing water; (d) reducing the pH of thefracturing water of step (c) to a level of less than about 5.5; and (e)adding an oxidizing agent to the fracturing water of step (d) to oxidizeoxidizable impurities in the fracturing water.

SUMMARY OF THE INVENTION

In one embodiment, the present invention includes a system for improvingoil recovery from a liquid source of oil, comprising: a membranecontactor in contact with a liquid source of oil; a heater/coolerconnected to at least one of the liquid sources of oil; and a membranecontactor system having one or more membrane contactors having a firstand a second surface, wherein at least one of the first or secondsurfaces coalesce one or more oils from the liquid source of oilallowing the coalesced oil to be collected on an opposite surface of themembrane, wherein a temperature increase of the liquid source of oil toenhance the oil recovery at the membrane contactor from the liquidsource of oil. In one aspect, the temperature increase of the liquidsource of oil is at least 0.1, 0.2, 0.3, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, 5, 16, 17, 18, 19, 20, 25, 30, 35, or 40 degreescentigrade. In another aspect, the temperature increase cause adifferential of at least 0.1, 0.2, 0.3, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, 5, 16, 17, 18, 19, 20, 25, 30, 35, or 40 degreescentigrade between the liquid source of oil and a collection fluid. Inanother aspect, the heater increases the temperature of the liquidsource of oil, a collection fluid, or both, wherein a temperaturedifferential is at least 0.1, 0.2, 0.3, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, 5, 16, 17, 18, 19, 20, 25, 30, 35, or 40 degreescentigrade between the liquid source of oil and a collection fluid. Inanother aspect, the cooler decreases the temperature of the liquidsource of oil, a collection fluid, or both, wherein a temperaturedifferential is at least 0.1, 0.2, 0.3, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, 5, 16, 17, 18, 19, 20, 25, 30, 35, or 40 degreescentigrade between the liquid source of oil and a collection fluid. Inanother aspect, the liquid source of oil is at least one of an oil-richstream, crude oil, transportation fuel, heating oil, refined petroleumproducts, petrochemicals, bio-oils, renewable oils, vegetable oils,reclaimed oils, waste oils, oil industry liquid streams, oilcontaminated water or brine, drilling mud, produced water and oil sandstailings. In another aspect, the membrane contactor is a hydrophobicmembrane or membrane module that comprises hollow fiber microporousmembranes. In another aspect, the membrane contactor is a hydrophobichollow fiber membrane comprising polyethylene, polypropylene,polyolefins, polyvinyl chloride (PVC), amorphous polyethyleneterephthalate (PET), polyolefin copolymers, poly(etheretherketone) typepolymers, surface modified polymers, mixtures or combinations thereof ora surface modified polymer that comprises polymers modified chemicallyat one or more halogen groups by corona discharge or by ion embeddingtechniques. In another aspect, the oil separated from the liquid sourceof oil by the membrane contactor is coalesced with the collection fluid,wherein the at least one collection fluid selected from non-polar fluid,alkanes such as hexane, aromatic fluid such as benzene, toluene, etherssuch as diethyl ether, halogenated fluid such as chloroform,dichloromethane, and esters such as ethyl acetate. In another aspect,the second surface is in contact with the collection fluid, which can bean oil previously recovered using a hollow fiber contactor. In anotheraspect, the liquid source of oil comprises at least one of mineral oil,vegetable oil, diesel fuel or oil, kerosene, naphtha, terpenes,petroleum, or aromatic or aliphatic hydrocarbons containing four orgreater carbon atoms or an isoparaffinic hydrocarbon selected from atleast one of isopar L, isopar C, isopar E, isopar G, isopar H, isopar K,isopar M, or isopar V, or synthetic thereof. In another aspect, thetemperature differential increases yield by at least 10%. In anotheraspect, the temperature differential increases yield by at least 10, 11,12, 13, 14, 15, 20, 25, 30, 35, 40, 50, 60, 70, or 75%.

Yet another embodiment of the present invention includes a method forrecovering oil from a liquid source of oil comprising the steps of:positioning a membrane contactor in contact with a liquid source of oil;heating or cooling at least one of the liquid source of oil or acollection fluid; and contacting a membrane contactor system having oneor more membrane contactors having a first and a second surface, whereinat least one of the first or second surfaces coalesce one or more oilsfrom the liquid source of oil allowing the coalesced oil to be collectedon the opposite surface of the membrane, wherein a temperaturedifferential between the liquid source of oil and the collection fluidenhances the oil recovery at the membrane contactor from the liquidsource of oil. In one aspect, the temperature increase of the liquidsource of oil is at least 0.1, 0.2, 0.3, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, 5, 16, 17, 18, 19, 20, 25, 30, 35, or 40 degreescentigrade. In another aspect, the temperature increase cause adifferential of at least 0.1, 0.2, 0.3, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, 5, 16, 17, 18, 19, 20, 25, 30, 35, or 40 degreescentigrade between the liquid source of oil and a collection fluid. Inanother aspect, the heater increases the temperature of the liquidsource of oil, a collection fluid, or both, wherein a temperaturedifferential is at least 0.1, 0.2, 0.3, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, 5, 16, 17, 18, 19, 20, 25, 30, 35, or 40 degreescentigrade between the liquid source of oil and a collection fluid. Inanother aspect, the cooler decreases the temperature of the liquidsource of oil, a collection fluid, or both, wherein a temperaturedifferential is at least 0.1, 0.2, 0.3, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11, 12, 13, 14, 5, 16, 17, 18, 19, 20, 25, 30, 35, or 40 degreescentigrade between the liquid source of oil and a collection fluid. Inanother aspect, the liquid source of oil is at least one of an oil-richstream, crude oil, transportation fuel, heating oil, refined petroleumproducts, petrochemicals, bio-oils, renewable oils, vegetable oils,reclaimed oils, waste oils, oil industry liquid streams, oilcontaminated water or brine, drilling mud, produced water and oil sandstailings. In another aspect, the membrane contactor is a hydrophobicmembrane or membrane module that comprises hollow fiber microporousmembranes. In another aspect, the membrane contactor is a hydrophobichollow fiber membrane comprising polyethylene, polypropylene,polyolefins, polyvinyl chloride (PVC), amorphous polyethyleneterephthalate (PET), polyolefin copolymers, poly(etheretherketone) typepolymers, surface modified polymers, mixtures or combinations thereof ora surface modified polymer that comprises polymers modified chemicallyat one or more halogen groups by corona discharge or by ion embeddingtechniques. In another aspect, the oil separated from the liquid sourceof oil by the membrane contactor is coalesced with the collection fluid,wherein the at least one collection fluid selected from non-polar fluid,alkanes such as hexane, aromatic fluid such as benzene, toluene, etherssuch as diethyl ether, halogenated fluid such as chloroform,dichloromethane, and esters such as ethyl acetate. In another aspect,the second surface is in contact with the collection fluid, which can bean oil previously recovered using a hollow fiber contactor. In anotheraspect, the liquid source of oil comprises at least one of mineral oil,vegetable oil, diesel fuel or oil, kerosene, naphtha, terpenes,petroleum, or aromatic or aliphatic hydrocarbons containing four orgreater carbon atoms or an isoparaffinic hydrocarbon selected from atleast one of isopar L, isopar C, isopar E, isopar G, isopar H, isopar K,isopar M, or isopar V, or synthetic thereof. In another aspect, thetemperature differential increases yield by at least 10%. In anotheraspect, the temperature differential increases yield by at least 10, 11,12, 13, 14, 15, 20, 25, 30, 35, 40, 50, 60, 70, or 75%.

In yet another embodiment, the present invention includes an apparatusfor improving oil quality of a liquid source of oil, comprising: areservoir that comprises the liquid source of oil; a membrane contactorin contact with a liquid source of oil and optionally a collectionfluid; and a heater/cooler connected to at least one of the liquidsource of oil or a collection fluid, wherein the membrane contactorcomprises one or more membrane contactors having a first and a secondsurface, wherein at least one of the first or second surfaces coalesceone or more oils from the liquid source of oil allowing the coalescedoil to be collected on the opposite surface of the membrane, wherein atemperature increase in the liquid source of oil or an increasedtemperature differential between the liquid source and a collectionfluid enhances the oil recovery at the membrane contactor from theliquid source of oil.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the features and advantages of thepresent invention, reference is now made to the detailed description ofthe invention along with the accompanying figures and in which:

FIG. 1 shows the remnants of an oil/water mixture after application ofthe present invention. The lower layer is water removed from theoil/water mixture and the upper layer is the small volume of theremaining oil/water mixture from the shell side of the membrane at theconclusion of the process that was not separated during the operation.

FIG. 2 is a graph that shows flux test results using an X50 hollow fibermembrane contactor with 20 m² surface area. Isopar L was flowed on theshell side of the membrane at up to 4 gallons per minute (˜15.1 L perminute) at a range of pressures. Oil that passed through the membrane tothe tube side was collected. The flux rate is determined based on theoil volume recovered from the tube side per minute.

FIG. 3 is a graph that shows flux test results using an X40 hollow fibermembrane contactor with 20 m² surface area. Isopar L was flowed on theshell side of the membrane at up to 4 gallons per minute (˜15.1 L perminute) at a range of pressures. Oil that passed through the membrane tothe tube side was collected. The flux rate is determined based on theoil volume recovered from the tube side per minute.

FIGS. 4A and 4B show samples of crude oil processed with the method. Thesamples of oil recovered from the contaminated oil have no visiblesolids (FIG. 4A) and no visible water (FIG. 4B).

FIGS. 5A and 5B show the flux of pure isopar L through a recentlycleaned X50 membrane.

FIGS. 6A and 6B show the flux history of X40 membranes with isopar L(FIG. 6A) and the flux history of X40 membranes and performance withcleaning in accordance with the present invention (FIG. 6B).

FIG. 7 shows a flow diagram of cleaning methods, comparing themanufacturer's recommended method to the modified methods establishedthrough this work.

FIG. 8 shows a graph of membrane conditioning using a generic, low-costhydrophobic liquid (diesel fuel).

DETAILED DESCRIPTION OF THE INVENTION

While the making and using of various embodiments of the presentinvention are discussed in detail below, it should be appreciated thatthe present invention provides many applicable inventive concepts thatcan be embodied in a wide variety of specific contexts. The specificembodiments discussed herein are merely illustrative of specific ways tomake and use the invention and do not delimit the scope of theinvention.

To facilitate the understanding of this invention, a number of terms aredefined below. Terms defined herein have meanings as commonly understoodby a person of ordinary skill in the areas relevant to the presentinvention. Terms such as “a”, “an” and “the” are not intended to referto only a singular entity, but include the general class of which aspecific example may be used for illustration. The terminology herein isused to describe specific embodiments of the invention, but their usagedoes not delimit the invention, except as outlined in the claims.

Previously, the present inventors have developed United States PatentApplication Publication No. 2011/0174734, filed by Seibert, et al.,which teaches the development and application of a novel non-polar oilrecovery process utilizing a non-dispersive oil recovery method tocoalesce and recover oil from a bio-cellular aqueous slurry is describedherein, relevant portions incorporated herein by reference. The processcan be used to recover, e.g., algal oil from a lysed algae slurry,recovery of Omega fatty acids from a bio-cellular aqueous feed, recoveryof Beta-carotene from a bio-cellular aqueous feed and for the removal ofoil from produced water in oil production and similar type applicationsthat would typically be conducted by gravity settling or centrifugation.The technique of the present invention utilizes a microporous hollowfiber (MHF) membrane contactor. The novel non-polar oil recovery processdescribed herein can be coupled to a collecting fluid (a non-polar fluidsuch as heptane, a biodiesel mixture or the previously recovered oil)that is circulated through the hollow fiber membrane. In cases where thepreviously recovered oil is used the recovered oil does not have to beseparated from the collection fluid, and separation costs can beeliminated.

Yet another example by the present inventors includes methods andsystems for non-dispersive insoluble oil recovery from aqueous slurries.U.S. Patent Application Publication No. 2012/0184759, filed by Kipp, etal., teaches the development and application of a novel non-polar oilrecovery process utilizing a non-dispersive fluid extraction method tocoalesce and recover oil from a lysed or non-lysed Yeast slurry using amicroporous hollow fiber (MHF) membrane contactor, relevant portionsincorporated herein by reference. More particularly, the presentinventors teach methods and systems for extracting one or more insolubleoils from a liquid source that comprises insoluble oils and yeast,comprising using one or more non-dispersive membrane contactors,comprising the steps of: pumping the liquid source comprising the one ormore oils from a reactor to the contactor; pumping a collection fluidthrough the one or more contactors; contacting the one or more oils inthe liquid source with the collection fluid pumped in the one or morecontactors; pumping a first stream from the contactor back to thereactor, wherein the first stream comprises the liquid source with theYeast without extracted oils, wherein the Yeast remain viable; andremoving a second stream from the contactor or the vessel, wherein thesecond stream comprises the collection fluid and extracted oils.

Another example by the present inventors includes additional methods andsystems for non-dispersive isolation and insoluble oil recovery fromaqueous slurries. U.S. Patent Application Publication No. 2012/0208247(relevant portions incorporated herein by reference), includes methodsand systems for removing one or more insoluble oils from a liquidsource, comprising one or more organisms, using one or morenon-dispersive membrane contactors, comprising the steps of: pumping theliquid source comprising the one or more oils from a reactor to thecontactor; pumping a collection fluid through the one or morecontactors; contacting the one or more oils in the liquid source withthe collection fluid pumped in the one or more contactors; pumping afirst stream from the contactor back to the reactor, wherein the firststream comprises the liquid source with the one or more organismswithout removed oils, wherein the one or more organisms remain viable;and removing a second stream from the contactor or the vessel, whereinthe second stream comprises the collection fluid and removed oils.

As used herein, the term “a source of oil” or “a liquid source of oil”encompasses a aqueous liquid that includes oil (where the amount ofwater or other hydrophobic liquid includes an oil or lipid), or a liquidsolution that is hydrophobic but that includes a separable oilcomponent.

The method of the present invention also includes a process to excludeoil insoluble materials from oil-rich liquid sources, e.g., crude oil,transportation fuel, heating oil, refined petroleum products,petrochemicals, bio-oils, renewable oils, vegetable oils, reclaimedoils, waste oils or oil sands tailings as non-limiting examples. Inaddition, oil-rich sources include fluids produced from oil and gasoperations that include water, brine, sand, rocks and other oilinsoluble liquids and solids that comprise hydrocarbons that the userwants to recover or remove from the oil-rich source. The oil-rich liquidstream may result from a process that involves initial steps to removephysically large solids by gravity settling, filtration and/orcentrifugation as non-limiting examples. The size restriction on thesolids is required to efficiently complete the removal of oil insolublematerials. Physically small solids (less than approximately 30 uM) canpass into the shell side of the hollow fiber contactor, but in order topass through the pores to the tube side, the solids would have to beless than approximately 50 nM. In practice, solids are too physicallylarge to pass through the pores.

The process allows water removal from liquid oil sources, non-limitingexamples such as oil industry wastes, crude oil, transportation fuel,heating oil, refined petroleum products, petrochemicals, bio-oils,renewable oils, vegetable oils, reclaimed oils, waste oils or oil sandstailings. Currently, oil is recovered by skimming following gravitysettling or centrifugation in combination often with up-frontfiltration, chemical addition or the like. A non-dispersive membranecontactor is not currently used to promote more rapid or efficient oilrecovery or clean up.

As used herein, the term “contaminated oil” encompasses an oil stream orpool that may contain one or more of the following in any combination;oils (hydrocarbons and hydrocarbon-rich molecules of commercial value),and, clay, rocks, sand, cells and/or cellular debris, insolubleparticulates having diameters from, e.g., 100 nm to 1000 micrometers,water, brine, salts, gums, drilling fluids or muds, solvents, lipophobicagents, lipophilic agents, inorganic or organic: molecules, oligomers orpolymers, solvents, and/or surfactants. In certain examples, the“contaminated oil” is an oil that is an “off-spec” oil or fuels that cannot be sold for the same price, and many require clean up prior to sale.Because “off-spec” oil has diminished value, the present invention hasimmediate use in oil clean up, with diverse, large commercialapplications.

As used herein, the term “oil” refers to, e.g., hydrocarbon orhydrocarbon-rich molecules including a complex mixture ofpetrochemicals, lipids, hydrocarbons, fatty acids, triglycerides,aldehydes, etc. The compounds included herein may be from, e.g., C₈ (jetfuel compatible) up to C₆₀ (motor oil compatible) or larger. As usedherein, a “membrane contactor” refers to a hydrophobic microporoushollow fiber membrane. Non-limiting examples of membrane contactorsinclude hydrophobic membrane or membrane module that comprises hollowfiber microporous membranes, e.g., hydrophobic hollow fiber membranemade from polyethylene, polypropylene, polyolefins, polyvinyl chloride(PVC), amorphous Polyethylene terephthalate (PET), polyolefincopolymers, poly(etheretherketone) type polymers, surface modifiedpolymers, mixtures or combinations thereof.

As used herein, the term “hydrophobic liquid” refers to liquids that arepartially or completely water immiscible. Non-limiting examples ofhydrophobic liquids for use with the present invention include mineraloil, vegetable oil, diesel fuel or oil, kerosene, naphtha, petroleum, oraromatic or aliphatic hydrocarbons containing four or greater carbonatoms. In one non-limited example, the hydrophobic liquid can be one ormore isoparaffinic hydrocarbon selected from at least one of isopar L,isopar C, isopar E, isopar G, isopar H, isopar K, isopar M, or isopar V,or synthetics thereof.

The system can also include, but does not require a collection fluid,which in one non-limiting example is a counterflowing collection fluid,which can be a solvent, diesel or biodiesel, oil, or mixtures thereof.

Liquid sources that are predominately oil that are contaminated can be“cleaned” using a microporous hollow fiber membrane. Water-in-oilemulsions, for example, can be separated, in which a high purity oil isgenerated from a mixture of oil with oil insoluble liquid (or solids,see below). An example of high purity can be an enrichment of 60, 70,80, 85, 90, 55, 96, 97, 98, 99 or 100% pure oil. The oil in the mixtureis separated by passing through the membrane; the water is left behind.This technique could be applied in various applications to remove waterfrom oil. In addition, the method will separate solids from oil, becausethe solids are too small to traverse the microscopic pores in the hollowfiber membrane that the oil passes through. Thus, an oil mixed withinsoluble solids and water can be passed through the hollow fibermembrane and an oil stream substantially devoid of water and solids willbe recovered. The system can be operated in a mode in which the waterremoved from the oil stream accumulates and is drained to allowcontinuous operation.

A water in oil emulsion was separated by exposure to a hollow fibermembrane. The oil passed through the membrane and was recovered on thetube side; the water remained on the shell side of the module. FIG. 1shows the remnants of the oil on the shell side after draining. Thewater in oil emulsion (top layer) still exists, but much of the waterhas been separated from the water and is now free water (bottom layer).

TABLE 1 Pure Oil Flux Test Results X50 3 gallons per minute 11.355liters per minute 10 psid 130 seconds to 4L, Trial 1 130 seconds to 4L,Trial 2 20 m{circumflex over ( )}2 surface area 1.538 flux rate (mL perm{circumflex over ( )}2 per second) 16% % flux 1.846 L per minute

TABLE 2 Pure Oil Flux Test Results X50 3.76 gallons per minute 14.2316liters per minute 30 psid 43 seconds to 4L, Trial 1 43 seconds to 4L,Trial 2 20 m{circumflex over ( )}2 surface area 4.651 flux rate (mL perm{circumflex over ( )}2 per second) 39% % flux 5.58 L per minute

TABLE 3 Pure Oil Flux Test Results X50 0 gallons per minute 0 liters perminute 50 psid 27 seconds to 4L, Trial 1 27 seconds to 4L, Trial 2 20m{circumflex over ( )}2 surface area 7.407 flux rate (mL perm{circumflex over ( )}2 per second) 8.89 L per minute pressure L perminute 10 1.846 30 5.58 50 8.89

TABLE 4 Pure Oil Flux Test Results X40 3.1 gallons per minute 11.7335liters per minute 12.5 psid 669 seconds to 4L, Trial 1 649 seconds to4L, Trial 2 20 m{circumflex over ( )}2 surface area 0.298953662 fluxrate (mL per m{circumflex over ( )}2 per second) 3% % flux 0.359 L perminute

TABLE 5 Pure Oil Flux Test Results X40 3.9 gallons per minute 14.7615liters per minute 30 psid 232 seconds to 4L, Trial 1 234 seconds to 4L,Trial 2 20 m{circumflex over ( )}2 surface area 0.854700855 flux rate(mL per m{circumflex over ( )}2 per second) 7% % flux 1.03 L per minute

TABLE 6 Pure Oil Flux Test Results 0 gallons per minute 0 liters perminute 50 psid 140 seconds to 4L, Trial 1 138 seconds to 4L, Trial 2 20m{circumflex over ( )}2 surface area 1.438848921 flux rate (mL perm{circumflex over ( )}2 per second) % flux 1.74 L per minute X40pressure L per minute 12.5 0.359 30 1.03 50 1.74

Tables 1 to 3 shows the flux test parameters and the results of the pureoil flux using the present invention using an X50 membrane system.Tables 4 to 6 shows the flux test parameters and the results of the oilseparation using the present invention using an X40 membrane system. Theresults of the flux tests from Tables 1 to 3 and Tables 4 to 5 aresummarized in the graphs of FIGS. 2 and 3, respectively.

FIGS. 4A and 4B shows samples of crude oil processed with the method.Briefly, two (2) gallons of crude oil, recovered by gravity separationand skimming, were further cleaned using the membrane. The contaminatedcrude oil was circulated through the shell side of an X50 membrane with1.4 m² surface area to allow the oil to coalesce to the tube side; thecontaminants were left on the shell side. Samples of the contaminatedoil and the cleaned oil were centrifuged at 12,000×g to pellet suspendedsolids and observe the presence of solids and water. The samples of oilrecovered from the contaminated oil have no visible solids (FIG. 4A) andno visible water (FIG. 4B).

FIGS. 5A and 5B show the flux of pure isopar L through a recentlycleaned X50 membrane. The membrane had been used extensively andrepeatedly with complex feedstocks, and cleaned multiple times accordingto the manufacturer's instructions. This conventional cleaning usessequential water, acid, base and isopropyl alcohol washes, followed bycomplete drying. The cleaning method is known to eventually reduce thefunctional lifespan of the membranes. Following cleaning, the membranespassed the manufacturer's quality control test. As shown in FIG. 5A andFIG. 5B, the oil flux rate of the clean membrane was poor, consistentwith a membrane approaching the end of its useful life. At theconclusion of the initial isopar L testing, the membrane was filled withisopar L, capped and set aside for approximately three weeks. Followinga three week soak in isopar L, the oil flux testing was repeated. Theflux rate of the membrane was dramatically improved by the prolongedisopar L soak.

FIGS. 6A and 6B show the flux history of X40 membranes with isopar L.Membranes were tested for isopar L flux when new. The membranes werethen exposed to two distinct oilfield produced waters. Followingexposure to oilfield water 1, the membranes were soaked in isopar L forseveral days and flux testing was repeated. The conventional cleaningmethod was not used. These results show that after exposure to complexfeedstocks, the membranes achieved flux rates approximately 75% of therates achieved when the membranes were new (FIG. 6A). Following exposureto oilfield water 2, membrane 1 was filled with isopar L when thetesting ended. By contrast, membrane 2 was capped and set aside forapproximately ten days without isopar L. To clean and restore themembranes, each was conditioned with isopar L for approximately 30minutes (1.75 gpm, 50 psi). During the conditioning, the performance ofthe membranes steadily improved (data not shown). At the conclusion ofthe conditioning, the flux rate of membrane 1 was nearly fully restoredto the flux rate prior to the reuse (FIG. 6B). By contrast, membrane 2'sflux was approximately 80% of the flux rate prior to the reuse.Immediate exposure to a hydrophobic liquid (isopar L) at shut downappeared to shorten the cleaning time for the membranes following oilexposure.

FIG. 7 shows the flow diagrams of cleaning methods. The flowchartlabeled Option 1 shows the manufacturer's recommended cleaning method.The flow diagrams labeled Options 2 and 3 shows the improved methods ofthe present invention that lead to an increased useful usage time of thepresent invention, the improved performance of the membrane onceperformance has degraded due to usage, or both improve useful life ofthe membrane and increased performance of the membrane after degradationof membrane performance but before the novel treatment of the presentinvention. Briefly, the methods begin with a start 10. In Options 1 and2, which are flowcharts for a method that can be used with usedmembranes that have reduced performance, an alcohol wash 12 (e.g.,methyl, ethyl, isopropyl or other alcohol) is used on either the shellor tube sides of the membrane (used herein interchangeably with firstand second side), which is followed by a caustic wash 14 most commonlyperformed on the shell side of the membrane until the solutionbreaks-through to the tube side of the membrane. Next, if the causticwash 14 does not lead to a breakthrough at step 16, then the alcoholwash step 12 is repeated followed by the caustic wash 14. If at step 16the caustic solution does breakthrough to the tube side, then an acidsolution 18 is then contacted with the shell side. Next, if the acidwash 18 does not lead to a breakthrough of the acid solution, then theprocess begins again with the alcohol wash 12. If the acid solutionbreaks-through to the tube side 20, then the membrane is washed at step22, e.g., using an inert gas such as nitrogen. In contrast to therecommendations of the manufacturer's cleaning process, the presentinventors have found a significant improvement in both the performancebut also the useful life of the membrane by adding an oil-soak orcirculation step 24 following the drying step 22. Based on thisobservation, the present inventors developed a novel pre-treatment forthe membrane in which, prior to any use, the membrane is pre-soaked 28in oil or by circulating oil on the shell, tube or both sides of themembrane. The cleaning and conditioning method disclosed herein isdramatically simpler, faster and less expensive than the methodrecommended by the manufacturer. The method disclosed herein is alsocompatible with rapid, high-efficiency start up for oil removalapplications. Furthermore, it is important to note that these membranesare designed for separating gases, thus, it is counterintuitive tocontact the membranes with any fluid, in particular any type of oil.

FIG. 8 shows the flux of diesel fuel through a used, unclean X40membrane. The membrane had been used with industrial wastewatercontaining oil. Following use, the membrane was rinsed with water, andthen set aside with no further treatment. Approximately six weeks later,the membrane was completely dry. Diesel fuel was circulated through themembrane for approximately 35 minutes at a flow rate of 1.75 gpm and 50psi. No collection fluid was used. The rate of flux of diesel fuel wasmonitored during the circulation by measuring the volume of dieselrecovered from the tube side of the membrane every two minutes(following a brief normalization period to establish steady stateoperating conditions). As shown in the FIG. 8, the initial flux rate ofthe membrane was approximately 1580 mL per minute. The flux rateimproved during continued exposure to diesel, reaching a flux rate of1950 mL per minute after 35 minutes of continuous exposure. The fluxrate of the dirty membrane improved by more than 20% during the test,establishing that a generic, low-cost hydrophobic liquid is sufficientto condition the membrane and improve function.

The skilled artisan will recognize that some streams will either have nosolids or solids that already meet the size selection criteria forprocessing (less than 10, 20, 30, 40 or 50 microns), so the stream maynot need any pre-processing. If it is the case that some of the solidswill stick to the membrane and cause a clog, a cleaning processes isused to remove the solids from the membrane to continue use. The presentinvention may also include a clog detector that determines if themembrane contactor system has become at least partially or fullyclogged. Whether or not a clog is detected (e.g., if a clog detector isnot used and rather a regular or sporadic cycle or maintenance is used),the invention may also include a system or method for cleaning themembrane contactor, e.g., physical-mechanical cleaning, use ofchemicals, backflow, pressurized water, brine or other solvents or othermethods for removing debris from the membrane contactor system. Thus,the present invention may also include one or more systems for cleaning,flushing and regenerating the membrane.

In certain examples, the streams may have been partially or completelygravity settled and/or may be predominantly oil with solids andcomparatively small amounts of water. To separate the solids from theoil it may be necessary to apply pressure to the stream as it enters thesolid removal system and/or the stream may have to be heated (in oneexample, steam is applied to the stream to both heat the stream andincrease the water content).

It was found that the present invention can be operated with or withouta counterflowing collection fluid. Therefore, the systems and methodscan operate with or without a collection fluid to process contaminatedoil.

Use of a non-dispersive contactor can recover oil from oil/water/solidsmixtures without recovering contaminating solids or water.

The present invention improves the recovery of oil by creating atemperature differential between a liquid source of oil and a collectionfluid across a non-dispersive contactor to recover oil from oil/water oroil/water/solids mixtures, thereby separating the oil the water and/orsolids. The present inventors found that the membrane contactor, unlikestandard filtration units, works by coalescing oil at the surface of themembrane. The coalesced oil then transfers across the membrane and canbe collected on the opposite side of the membrane contactor in, e.g., acollection fluid.

Separation of oil-rich streams from hydrophilic liquids is difficult andexpensive with conventional techniques, like centrifugation or gravitysettling. The new method shows that liquid sources can be heated orcooled as a way to improve separation of phases by the membranecontactor and that the results are not intuitive. Other methods,including surfactants and emulsion breaking chemicals, can also be usedto improve the character of the feedstock, making it easier to separate.However, such methods require an additional step to separate or recoverthe surfactants. Alternately, or in addition, the recirculatingcollection fluid can be heated or cooled, as appropriate to improveseparation. The skilled artisan will recognize that, following theteachings herein, the optimum differential can be determined by simplycontacting the liquid source of oil with the membrane contactor,creating a temperature differential between the liquid source of oil andthe collection fluid, and measuring the change in yield. In one example,the collection fluid or the liquid source of oil can be placed outside abuilding, wherein the external temperature of the building is differentfrom the internal temperature and isolation of oil is conducted.Depending on ambient temperature, the present invention can becustomized to meet local environmental conditions, e.g., if operating ina location with an average temperature of 25° C. or higher, the interiorof the building may be cooled, while in locations with lower ambienttemperatures, the interior of the building may be heated.

In another embodiment, the method is distinct from what has beenpreviously disclosed in that it is specifically designed to make themembrane separation work more effectively by heating or cooling arecirculating collection fluid instead of the entire liquid source ofoil or feedstock.

The objective of this study was to cause the oil to transfer fasteracross the membrane walls and to measure the parameters that caused achange in oil recovery. The following benefits were found using thepresent invention, namely, (1) faster recovery of oil from water; (2)recovery of oil without water; and (3) faster clean-up of oil.

The present invention has several important applications, including butnot limited to: (1) clean-up of “off-spec” oil, oil products, recycledoil, etc.; (2) oil product recovery from water; and (3) water clean up.It also permits for removal of oil from liquid sources containing solidsof similar density to water and oil.

This study used identical materials at different temperatures todetermine the flux rate of oil. Operating conditions will be the same asabove, the only variable will be the temperature. Isopar L can be cooledby placing it in the freezer. Isopar L can be heated by placing itoutside in the sun (100° F.+ or about 38° C.+).

The study records the time to flux 3 L of isopar L in triplicate at thetwo different temperatures. An X40 membrane will be used (ID:500056788).Temperatures were determined using a heat gun. Operation at 1.5 gpm and50 psi differential pressure.

TABLE 7 Enhanced Yield of Oil. Round seconds temp (F) mL per sec Datacollection, cooled isopar L lrst 89 72 33.7 2nd 87 76 34.5 3rd 80 8437.5 Data collection, heated isopar L lrst 66 97 45.5 2nd 65 97 46.2 3rd64 98.4 46.9Comparing the 2nd runs in each group

21 degree temperature difference

25% increase in flux rate

It is contemplated that any embodiment discussed in this specificationcan be implemented with respect to any method, kit, reagent, orcomposition of the invention, and vice versa. Furthermore, compositionsof the invention can be used to achieve methods of the invention.

It will be understood that particular embodiments described herein areshown by way of illustration and not as limitations of the invention.The principal features of this invention can be employed in variousembodiments without departing from the scope of the invention. Thoseskilled in the art will recognize, or be able to ascertain using no morethan routine experimentation, numerous equivalents to the specificprocedures described herein. Such equivalents are considered to bewithin the scope of this invention and are covered by the claims.

All publications and patent applications mentioned in the specificationare indicative of the level of skill of those skilled in the art towhich this invention pertains. All publications and patent applicationsare herein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually indicated to be incorporated by reference.

The use of the word “a” or “an” when used in conjunction with the term“comprising” in the claims and/or the specification may mean “one,” butit is also consistent with the meaning of “one or more,” “at least one,”and “one or more than one.” The use of the term “or” in the claims isused to mean “and/or” unless explicitly indicated to refer toalternatives only or the alternatives are mutually exclusive, althoughthe disclosure supports a definition that refers to only alternativesand “and/or.” Throughout this application, the term “about” is used toindicate that a value includes the inherent variation of error for thedevice, the method being employed to determine the value, or thevariation that exists among the study subjects.

As used in this specification and claim(s), the words “comprising” (andany form of comprising, such as “comprise” and “comprises”), “having”(and any form of having, such as “have” and “has”), “including” (and anyform of including, such as “includes” and “include”) or “containing”(and any form of containing, such as “contains” and “contain”) areinclusive or open-ended and do not exclude additional, unrecitedelements or method steps.

The term “or combinations thereof” as used herein refers to allpermutations and combinations of the listed items preceding the term.For example, “A, B, C, or combinations thereof” is intended to includeat least one of: A, B, C, AB, AC, BC, or ABC, and if order is importantin a particular context, also BA, CA, CB, CBA, BCA, ACB, BAC, or CAB.Continuing with this example, expressly included are combinations thatcontain repeats of one or more item or term, such as BB, AAA, AB, BBC,AAABCCCC, CBBAAA, CABABB, and so forth. The skilled artisan willunderstand that typically there is no limit on the number of items orterms in any combination, unless otherwise apparent from the context.

As used herein, words of approximation such as, without limitation,“about”, “substantial” or “substantially” refers to a condition thatwhen so modified is understood to not necessarily be absolute or perfectbut would be considered close enough to those of ordinary skill in theart to warrant designating the condition as being present. The extent towhich the description may vary will depend on how great a change can beinstituted and still have one of ordinary skilled in the art recognizethe modified feature as still having the required characteristics andcapabilities of the unmodified feature. In general, but subject to thepreceding discussion, a numerical value herein that is modified by aword of approximation such as “about” may vary from the stated value byat least ±1, 2, 3, 4, 5, 6, 7, 10, 12 or 15%.

All of the compositions and/or methods disclosed and claimed herein canbe made and executed without undue experimentation in light of thepresent disclosure. While the compositions and methods of this inventionhave been described in terms of preferred embodiments, it will beapparent to those of skill in the art that variations may be applied tothe compositions and/or methods and in the steps or in the sequence ofsteps of the method described herein without departing from the concept,spirit and scope of the invention. All such similar substitutes andmodifications apparent to those skilled in the art are deemed to bewithin the spirit, scope and concept of the invention as defined by theappended claims.

REFERENCES

-   U.S. Pat. No. 8,128,827-   U.S. Pat. No. 7,186,344-   United States Patent Application Publication No. 2010/0173806-   United States Patent Application Publication No. 2005/0098504

What is claimed is:
 1. A system for improving oil recovery from a liquidsource of oil, comprising: a membrane contactor in contact with a liquidsource of oil; a heater/cooler connected to at least one of the liquidsources of oil; and a membrane contactor system having one or moremembrane contactors having a first and a second surface, wherein atleast one of the first or second surfaces coalesce one or more oils fromthe liquid source of oil allowing the coalesced oil to be collected onan opposite surface of the membrane, wherein a temperature increase ofthe liquid source of oil to enhance the oil recovery at the membranecontactor from the liquid source of oil.
 2. The system of claim 1,wherein the temperature increase of the liquid source of oil is at least0.1, 0.2, 0.3, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 5,16, 17, 18, 19, 20, 25, 30, 35, or 40 degrees centigrade.
 3. The systemof claim 1, wherein the temperature increase cause a differential of atleast 0.1, 0.2, 0.3, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,5, 16, 17, 18, 19, 20, 25, 30, 35, or 40 degrees centigrade between theliquid source of oil and a collection fluid.
 4. The system of claim 1,wherein the heater increases the temperature of the liquid source ofoil, a collection fluid, or both, wherein a temperature differential isat least 0.1, 0.2, 0.3, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13,14, 5, 16, 17, 18, 19, 20, 25, 30, 35, or 40 degrees centigrade betweenthe liquid source of oil and a collection fluid.
 5. The system of claim1, wherein the cooler decreases the temperature of the liquid source ofoil, a collection fluid, or both, wherein a temperature differential isat least 0.1, 0.2, 0.3, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13,14, 5, 16, 17, 18, 19, 20, 25, 30, 35, or 40 degrees centigrade betweenthe liquid source of oil and a collection fluid.
 6. The system of claim1, wherein the liquid source of oil is at least one of an oil-richstream, crude oil, transportation fuel, heating oil, refined petroleumproducts, petrochemicals, bio-oils, renewable oils, vegetable oils,reclaimed oils, waste oils, oil industry liquid streams, oilcontaminated water or brine, drilling mud, produced water and oil sandstailings.
 7. The system of claim 1, wherein the membrane contactor is ahydrophobic membrane or membrane module that comprises hollow fibermicroporous membranes.
 8. The system of claim 7, wherein the membranecontactor is a hydrophobic hollow fiber membrane comprisingpolyethylene, polypropylene, polyolefins, polyvinyl chloride (PVC),amorphous polyethylene terephthalate (PET), polyolefin copolymers,poly(etheretherketone) type polymers, surface modified polymers,mixtures or combinations thereof or a surface modified polymer thatcomprises polymers modified chemically at one or more halogen groups bycorona discharge or by ion embedding techniques.
 9. The system of claim1, wherein the oil separated from the liquid source of oil by themembrane contactor is coalesced with the collection fluid, wherein theat least one collection fluid selected from non-polar fluid, alkanessuch as hexane, aromatic fluid such as benzene, toluene, ethers such asdiethyl ether, halogenated fluid such as chloroform, dichloromethane,and esters such as ethyl acetate.
 10. The system of claim 1, wherein thesecond surface is in contact with the collection fluid, which can be anoil previously recovered using a hollow fiber contactor.
 11. The systemof claim 1, wherein the liquid source of oil or a collection fluidcomprises at least one of mineral oil, vegetable oil, diesel fuel oroil, kerosene, naphtha, terpenes, petroleum, or aromatic or aliphatichydrocarbons containing four or greater carbon atoms or an isoparaffinichydrocarbon selected from at least one of isopar L, isopar C, isopar E,isopar G, isopar H, isopar K, isopar M, or isopar V, or syntheticthereof.
 12. The system of claim 1, wherein the temperature differentialincreases yield by at least 10%.
 13. The system of claim 1, wherein thetemperature differential increases yield by at least 10, 11, 12, 13, 14,15, 20, 25, 30, 35, 40, 50, 60, 70, or 75%.
 14. A method for recoveringoil from a liquid source of oil comprising the steps of: positioning amembrane contactor in contact with a liquid source of oil; heating orcooling at least one of the liquid source of oil or a collection fluid;and contacting a membrane contactor system having one or more membranecontactors having a first and a second surface, wherein at least one ofthe first or second surfaces coalesce one or more oils from the liquidsource of oil allowing the coalesced oil to be collected on the oppositesurface of the membrane, wherein a temperature differential between theliquid source of oil and the collection fluid enhances the oil recoveryat the membrane contactor from the liquid source of oil.
 15. The methodof claim 14, wherein the temperature increase of the liquid source ofoil is at least 0.1, 0.2, 0.3, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,12, 13, 14, 5, 16, 17, 18, 19, 20, 25, 30, 35, or 40 degrees centigradebetween the liquid source of oil and a collection fluid.
 16. The methodof claim 14, wherein the temperature differential is at least 0.1, 0.2,0.3, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 5, 16, 17, 18,19, 20, 25, 30, 35, or degrees centigrade between the liquid source ofoil and a collection fluid.
 17. The method of claim 14, furthercomprising a heater increases the temperature of the liquid source ofoil, the collection fluid, or both, wherein a temperature differentialis at least 0.1, 0.2, 0.3, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,13, 14, 5, 16, 17, 18, 19, 20, 25, 30, 35, or 40 degrees centigradebetween the liquid source of oil and a collection fluid.
 18. The methodof claim 14, further comprising a cooler decreases the temperature ofthe liquid source of oil, the collection fluid, or both, wherein atemperature differential is at least 0.1, 0.2, 0.3, 0.5, 1, 2, 3, 4, 5,6, 7, 8, 9, 10, 11, 12, 13, 14, 5, 16, 17, 18, 19, 20, 25, 30, 35, or 40degrees centigrade between the liquid source of oil and a collectionfluid.
 19. The method of claim 14, wherein the liquid source of oil isat least one of an oil-rich stream, crude oil, transportation fuel,heating oil, refined petroleum products, petrochemicals, bio-oils,renewable oils, vegetable oils, reclaimed oils, waste oils, oil industryliquid streams, oil contaminated water or brine, drilling mud, producedwater and oil sands tailings.
 20. The method of claim 14, wherein themembrane contactor is a hydrophobic membrane or membrane modulecomprises hollow fiber microporous membranes.
 21. The method of claim14, wherein the membrane contactor is a hydrophobic hollow fibermembrane comprises polyethylene, polypropylene, polyolefins, polyvinylchloride (PVC), amorphous polyethylene terephthalate (PET), polyolefincopolymers, poly(etheretherketone) type polymers, surface modifiedpolymers, mixtures or combinations thereof or a surface modified polymerthat comprises polymers modified chemically at one or more halogengroups by corona discharge or by ion embedding techniques.
 22. Themethod of claim 14, wherein the oil separated from the liquid source ofoil by the membrane contactor is coalesced with the collection fluid,wherein the at least one collection fluid selected from non-polar fluid,alkanes such as hexane, aromatic fluid such as benzene, toluene, etherssuch as diethyl ether, halogenated fluid such as chloroform,dichloromethane, and esters such as ethyl acetate.
 23. The method ofclaim 14, wherein the second surface is in contact with a collectionfluid that can be an oil previously recovered using a hollow fibercontactor.
 24. The method of claim 14, wherein the liquid source of oilcomprises at least one of mineral oil, vegetable oil, diesel fuel oroil, kerosene, naphtha, terpenes, petroleum, or aromatic or aliphatichydrocarbons containing four or greater carbon atoms, isoparaffinichydrocarbon is selected from isopar L, isopar C, isopar E, isopar G,isopar H, isopar K, isopar M, or isopar V, or synthetic thereof.
 25. Themethod of claim 14, wherein the temperature differential increases yieldby at least 10%.
 26. The method of claim 14, wherein the temperaturedifferential increases yield by at least 10, 11, 12, 13, 14, 15, 20, 25,30, 35, 40, 50, 60, 70, or 75%.
 27. An apparatus for improving oilquality of a liquid source of oil, comprising: a reservoir thatcomprises the liquid source of oil; a membrane contactor in contact witha liquid source of oil and optionally a collection fluid; and aheater/cooler connected to at least one of the liquid source of oil or acollection fluid, wherein the membrane contactor comprises one or moremembrane contactors having a first and a second surface, wherein atleast one of the first or second surfaces coalesce one or more oils fromthe liquid source of oil allowing the coalesced oil to be collected onthe opposite surface of the membrane, wherein a temperature increase inthe liquid source of oil or an increased temperature differentialbetween the liquid source and a collection fluid enhances the oilrecovery at the membrane contactor from the liquid source of oil.